Armature turning and undercutting lathe



22, 1933- o. c. BLOMGREN ARMATURE TURNING AND UNDERCUTTING LATHE 1933- 0. c. BLOMGREN ARMATURE TURNING AND UNDERCUTTING LATHE Filed Nov. 27, 1931 s Sheets-Sheet 2 HIM j Aug. 22, 1933. Q Q BLQMGREN 1,923,416

ARMATURE TURNING AND UNDERCUTTING LATHE Filed Nov. 27, 1931 a Sheets-Sheet a I zz 2 J6 1 Patented Aug. 22, 1933 UNITED STATES PATENT OFFICE Oscar C.Blmgren, Winnetka, 111.

Application November 27, 1931 Serial No. 577,425

14 Claims.

My invention relates to armature conditioning tools and has to do more particularly with lathe structure for turning. and undercutting commutators.

One of the objects of my invention is to provide a novel form of lathe structure for the above purposes. which isv adapted to support the armature for rotational movement preferably in vertical or upwardly-directed position upon a center-support thereby providing a better. balanced and smoother operating. structure and insuring a better and more uniform finish in the. armature dressing operation.

Another object is to provide an inexpensive structure of the foregoing character which is of compact form, easily handled and adjusted and which is well adapted for small garage service.

In automotive, and related, service work, one may be called upon to dress. the commutators of several different types of armatures. These armatures may vary as toshaft diameters, shaft lengths, the provision of suitable shaft centers", and the like- In tools heretofore employed for dressing armatures considerable inconvenience 4 has, therefore, been experienced due to these differences. Such variations, in the use of prior structures, make it quite expensive for one to properly equip for armature service work due to the necessity of acquiring adapter accessories in order to be in position to dress all kinds of armatures. A further object of my invention is to provide novel chuck structure which has universal adaptability to various diameter and length armature shafts regardless whether the same are provided with. the usual. centers, whereby one tool may well serve for the dressing of substantially all types of armatures.

Additional objects are to provide a tool which may be readily and quickly adjusted for both turning and undercutting operations, a common cutter device being employed for this purpose; to provide a tool which requires a minimum of skill tooperate and which is of such durability as to render efficient service over a long period of time; and to provide a portable type of tool which may be readily and easily moved by the operator from place to place to facilitate armature-dressing operations.

Other objects and advantages will become apparent as this description progresses and by reference to the drawings in which,

Figure 1 is an elevational View, partially in section, of. one form of lathe structure embodying my invention and illustrating an armature in position to be dressed;

Fig. 2 is a horizontal section takensubstantially on line 2-2 of Fig. 1;

Fig. 3 is an enlarged sectional view taken substantially in the same position as Fig. 2 but showing the tool in position for undercutting;

Fig. 1 is a separated top plan view of the motordriven chuck structure shown in Fig. 1;

Fig. 5 is a partial elevational view of another adaptation of the structureshown in Fig. 1 and illustrating a modified form of. motor-driven 65, chuck structure;

Fig. 6 is a section taken substantially on line 6-6 of Fig. 5;

Fig. '7 is an enlarged vertical sectional view of the motor-driven chuck structure of Fig. 5;v and 71).

Fig. 8 is a section taken substantially on line 8-8 of. Fig. '7.

Referring particularly to the arrangement of Fig. 1, the tool illustrated comprises a base 10 fixedly supporting an upright standardll which.- is, preferably, of rectangular shape in cross section. This standard 11 slidably supports a telescoping support casing 12 of similar shape in cross section to prevent rotation of the same relative to the standard 11. The casing 12 is held in a plurality of predetermined, verticallyadjusted positions upon the standard 11 by a plurality of set screws 13 carried by the casing 12, the pointed ends 13 of which are adapted to seat in V-shaped sockets 11 in the standard 11. The upper'end of the support member 12 is reduced in size as at 14 and is extended inwardly at right angles, and in a direction parallel with the base 10, providing a center-support arm 15. The end of arm 15 terminates in a chuck ring 16, the center of the bore of which is on center with respect to the work as will be seen hereinafter. The bore of the chuck ring 16 is threaded to receive'a threaded center stem 19 which is adapted to be locked in adjusted position by nut 20. The armature structure, illustrated at 21, may be provided with a shaft, the ends 22 and 22 of which may be respectively supported on center by the center stem 19 and the motor chuck 18. The base 10, at a point laterally 1 spaced from the standard 11, supports a vertical motor 17, the vertical drive shaft (not shown in detail) of which supports the universal chuck structure 18 on center with respect to the chuck lo 0 ring 16 and the work.

The expense heretofore necessary to properly equip an automotive service garage for servicing of the various kinds of automotive-used, and the like, armatures on the market, as hereinabove explained, has been such as to practically prohibit I c chuck 18. 5s

. manner as to permit the free of different diameters.

. the center head 24 against rotation. The 45 the use of tools of this character in the smaller garage service work. My invention provides a tool which is inexpensive and is universally applicable to practically all known armature structures which one may be called upon to service in automotive repair work; thereby placing armature dressing operations: within the service limits of even the smaller service garages. To this end, one of the important features of my invention is the provision of chuck means which is universally adaptable to a wide range of armature structures, regardless of the above-mentioned variations therein.

Specifically, the chuck structure 18 which is connected to and driven by the motor shaft, takes the form of a member (Figs 1 and 4) having an inverted cone-shaped socket 18 the tapering wall of which is provided with a plurality (preferably three) of outwardly projecting and relatively sharp-edged ribs 23. This chuck socket is adapted to wedgingly receive the lower end 22* of the armature shaft and, due to the weight of the armature and the relative sharp edge of the ribs 23, the shaft 22 is grippingly engaged and the armature is rotated with its axis in vertical position as the motor shaft rotates. This chuck structure, with the armature shaft end en gaged on center with the pointed end of the center stem 19, insures self-adjustment of the armature shaft end 22 to an on center position as will be readily appreciated.

The flaring shape of the chuck socket l8 provides for the reception of armature shaft ends In the event that the armature shaft may be of a diameter which will not permit entry of the same within the chuck socket 18 I may employ the motor-driven chuck structure illustrated in Figs. 5, 7 and 8. Specifically, I provide a removable center head 24 having its lower body portion tapered complementally to the taper of the chuck socket 18 and having longitudinal grooves 24 which align with and receive the chuck socket ribs 23 for holding upper body portion 24 of this center head is coneshaped and pointed to engage in the center opening 25 in the enlarged shaft end 22. To effect a positive drive between the chuck structure 18 and the shaft end 22, I provide a suitable form of lathe connection or dog 26 having collar portion 26 secured to the shaft end 22 by a lock screw 27 and a depending shank 26 which engages a laterally-extending pin 28 carried by the Obviously, as the motor shaft rotates, rotating the chuck 18, the armature 21 is rotated.

Adjustment of the casing support 12 and the center stem 19 will accommodate armature shafts of different lengths within predetermined limits. However, such shaft-length limits may be exceeded and, in that case, as illustrated in Fig. 5, the lengthened end 22 (Fig. 5) of the shaft is supported as follows: The chuck collar 16 is provided with a plurality (preferably three) annularly arranged, equally spaced center-support 65' screws 29 which are manually and independently adjustable as will be obvious from Figs. 5 and 6. In operation, the armature 21 is mounted in position upon the motor chuck with its shaft end 22 projecting upwardly through the opening in the collar 16, and the screws 29 are adjusted to similar extents into engagement with the shaft end 22 supporting the same on center for rotative movement. The screws 29 are set up in such a rotation of the armature 21 but their relationship is such as to maintain the shaft centered upon its lower center support for the turning movement of the armature. This centering arrangement is not limited to use in conjunction with the motor chuck structure shown in Fig. 5, but may be used equally well with the arrangement shown in Fig. 1, or otherwise.

The turning and undercutting operations are accomplished by means of a single knife or cutter device 30 supported and operated in the following manner: A rectangularly-shaped collar 31 is slidably mounted on the upper end of the support member 12 and it is provided with an arm 32 extending in lateral direction parallel with the base 10 and at right angles to the support 12. This arm 32 supports another arm 33 which is provided with a longitudinal slot 33 receiving the stem of a screw 34 carried by the arm 32. With this arrangement, the arm 33 which carries the cutter 30 may be adjusted to the desired ex tent toward and from the armature by merely loosening the screw 34 and moving the arm 33 relative to the arm 32. The screw 34 when tightened holds these two arms in their predetermined adjusted position. The arm 33 is provided with a thickened head 35 having a rectangularlyshaped opening therethrough for receiving the similarly-shaped body of the cutter 30, which opening is projected at an angle to the longitudinal center line of the arm 33 and toward the work. The cutter is adjustable in its support 35 and is held in adjusted position by a set screw 36. Furthermore, the cutter is provided at one end with a turning edge 30 and at the other end with an undercutting edge 30' these cutting edges being, preferably,of the shape best illustrated in Figs. 2 and 3. As will be understood, for best operation of the dressed armature, after the turning of the commutator, the mica or other insulating material between the commutator segments 38 should be undercut; and it has been found from practical demonstration that best undercutting results are accomplished by arranging the cutting edge 30 so that it provides a V-shaped groove in the mica 37 between the commutator segments 38 with the apex of the V spaced substantially equal distances from the adjacent edges of the commutator segments (Fig. 3).

In the operation of the foregoing structure, for turning of the commutator 39, the motor is set in operation to rotate the armature structure. The cutter 30, having been properly adjusted with its edge 30 projected toward the commutator, is then moved up and down in engagement with the commutator, accomplishing the turning operation to the desired extent. When undercutting, the cutter edges are reversed, the edge 30 projecting toward the work. The armature is turned to a position wherein the edge 30 of the cutter engages between the commutator segments and, the armature remaining stationary, the knife is moved vertically to make the cut. Although I use a single, double-edge cutter inthe preferred form, separate cutters with the proper single edges may be employed for turning and undercutting operations without departing from my invention. The movement of the cutter in both of these instances is accomplished by means of suitable handle and operating connections. Specifically, I may employ a handle 40 pivotally supported at 41 by a rectangularly-shaped collar 42 secured in adjusted position upon the support casing 12 by set screw 43. This collar 42 is ad-.

as a limiting stop for the knife-carrying, slidable collar 31. In this manner, the lowermost position of the cutter is predetermined so that the cutter may be moved over and longitudinally along only a predetermined surface .to be cut. This is, of course, desirable to avoid injury to the armature part not to be dressed. The handle 40 pivotally supports, as at 44, a link 45 which is, in turn, pivotally connected, as at 46, to the collar 31. The relationship ofthe pivots 41, 44, and 46 is such that by grasping the outer end of the handle 40 and moving the same up and down, the collar 31 and cutter 30 are readily and easily moved up and down along the support 12. The downward movement of the-handle 40 is yieldingly opposed by a spring 47 connected at one end to the collar 31 and at the otherend to the handle pivot 44. This spring, also, tends to return the collar 31 and cutter 30 to their uppermost positions (Fig. 1).

From the foregoing, it will be appreciated that my invention is well adapted to the accomplishment of the objects hereinabove stated. Itwill be understood that while I have shown several adaptations of my invention, other changes in details and arrangements of parts may be made without departing from the spirit and scope of my invention as defined by the claims which follow.

I claim:

1. In structure of the class described, the combination of a base, an upwardly-projecting standard carried by said base, a rotatable chuck structure supported by said base with its axis of :rotation projected in upward direction substantially parallel with said standard, means for rotating said chuck structure, a support member mounted on said standard for longitudinal ad- .justment relative thereto and having a laterallyextending arm, a centering and supporting device carried by said arm in alignment with the axis of said chuck structure, and a cutter adjustable longitudinally of the armature being dressed.

2. In structure of the class described, a portable, self-contained unit comprising a base, an upwardly-extending standard supported by said base, a laterally-extending arm supported by said standard, an armature centering structure supported by said arm, rotatable armature centering and supporting structure supported by said base with the axis of such structure projected in upward direction in alignment with the axis of said armature centering structure, means for rotating said armature centering and supporting structure with the latter supporting a substantial part of the weight of the armature, a cutter supported by said standard for longitudinal reciprocation relative to the armature, and means for reciprocating said cutter.

3. In a tool of the class described, the combination of a base, a standard carried thereby and projecting vertically therefrom, a rotatable armature support carried by said base and having its axis of rotation projecting in vertical direction substantially parallel with said standard, an arm projecting laterally from and at substantially right angles to said standard, armature centering and rotation-guide means carried by said arm in alignment with said rotatable armature support, a cutter carrier supported by said standard for vertical slide movement, a cutter adjustably supported by said carrier, means for adjusting said carrier within itself for and means supported by said standard and operatively connected to saidcarrier for reciprocating said cutter vertically.

4. In a'tool of the class described, the combination of a base, a standard carried thereby, a rotatable armature support carried by said base and having its axis of rotation projecting substantially parallel with said standard, an arm projecting laterally from and at substantially right angles to said standard, armature centering and rotation-guide means carried by said arm :in alignment with said rotatable armature support, a cutter carrier supported by said stand- :ard for slide movement thereon, a cutter adjustably supported by said carrier, means for adjusting said carrier within itself for projecting said cutter relative to the armature, and means including reciprocation-limiting stop means supported by said standard and operatively connected to said carrier for reciprocating said cutter relative to the armature.

5. In structure of the class described, a portable, self-contained unit comprising a base, a vertically-projecting standard carried by said base, a motor carried by said base and having a vertically-projecting drive shaft, means carried by said drive shaft for centering and supporting one end of the armature shaft, a vertically-ad justable support member carried by said standard and having a lateral arm, means carried by said arm adapted for centering and supporting the other end of said armature shaft, and a cutter supported by said support member for sliding movement relative thereto and to the accommodate different size armature shafts, said stationary support having provision for securement therein of removable shaft centering means.

'7. In structure of the class described, a base, a vertical standard supported thereby, a substantially horizontal arm supported by said standard, a chuck supported by said base and rotatable about a vertical axis and shaped to receive a plurality of different-size armature shafts for supporting and centering the armature, means for rotating said chuck, a ring-shaped member carried by said arm with its axis on center with respect to the axis of said rotatable chuck, and a centering stem carried by said ring member and adapted to engage the adjacent armature shaft end on center.

8. In structure of the class described, a base, a standard supported thereby, an arm supported by said standard, a rotatable chuck adapted to ac commodate a plurality of different-size armature shafts for supporting and centering the armature, means for rotating said chuck, a ring-shaped member carried by said arm with its axis on center with respect to the axis of said rotatable chuck, and elements carried by said ring-shaped member and adjustable toward and from the center thereof for supporting and centering the adjacent end of the armature shaft projected through said ring-shaped member.

9. In structure of the class described, a base, a standard supported thereby, an arm supported by said standard, a rotatable chuck adapted to accommodate a plurality of different-size arma ture shafts for supporting and centering the armature, means for rotating said chuck, a ring member carried by said arm with its axis on center with respect to the axis of said rotatable chuck, and a plurality of equally-spaced, radially disposed screw members carried by said ring member and adjustable toward the center of said ring member to engage and center and support the adjacent end of the armature shaft for rotation of the armature.

10. In structure of the class described, means for supporting and centering the armature in position for rotation which comprises a socket member in which the lower end of the armature shaft is received, means associated with said socket for grippingly engaging one end of the armature shaft for rotational movement thereof, means for rotating said lower socket member, an upper and vertically spaced center stem supported with its axis on center with respect to the axis of said socket member, and means for adjusting said stem to engage one of its ends on center with the upper end of the armature shaft.

11. In structure of the class described, means for supporting and centering the armature in position for rotation which comprises a socket member in which one end of the armature shaft is received, means associated with said socket for grippingly engaging said one end of the armature shaft for rotational movement thereof, a second stationary socket member having its axis on center with respect to said first socket member, and. means associated with said second socket member adapted to engage and hold the other end of the armature shaft centered while the armature is in rotation.

12. In structure of the class described, means for supporting and centering the armature in position for rotation about an upwardly-directed axis which comprises a member having an inverted cone-shaped socket, the axis of which is disposed in vertical direction to receive one end of a vertically-disposed armature shaft, said socket having spaced, longitudinally-extending ribs around its wall against which the end of the armature shaft seats, drive-engagement between the armature shaft and said ribs being effected through the pressure imposed by the weight of the armature.

13. In structure of the class described, means for supporting and centering the armature in position for rotation about a vertical axis which comprises a member having an inverted coneshaped socket, ribs extending longitudinally along the wall of said socket, and a center-support device having one end of its body portion shaped complementally to said socket and grooved to receive said ribs, and having its other end portion pointed and adapted to project beyond said socket to engage the end of the armature shaft, means for interlocking said socket member and armature shaft for rotation to-- gether, and means for rotating said socket member.

14. In a tool of the class described, a base, a standard carried thereby, a chuck structure rotatable about an upwardly-directed axis and adapted to bear the weight of the armature, and means for rotating said chuck structure and armature, a support member mounted upon said standard for longitudinal adjustment relative thereto, a stationary centering device carried by said member in alignment with said chuck structure and adapted to engage the armature shaft, a cutter supported by said member for reciprocation and for adjustment toward and from the armature, and means supported by said member for reciprocating said cutter.

OSCAR C. BLOMGREN. 

